Operating mechanism for high voltage switch



y 1968 J. BERNATT ETAL 3,382,330

Filed July 25, 1967 4 Sheets-Sheet l mug} May 7, 1968 J. BERNATT ETAL 3,382,330

OPERATING MECHANISM FOR HIGH VOLTAGE SWITCH Filed July 25, 1967 4 Sheets-Sheet 2 FIG.

y 7, 1968 J. BERNATT ETAL 3,382,330

OPERATING MECHANISM FOR HIGH VOLTAGE SWITCH OUTPUT TRAVEL, ROTATION DEGREES (97 Filed July 25. 1967 4 Sheets-Sheet 5 g k f8 Q n ll, 0: out I Lu Q It Q u m S Q E D m Lu 2 E a 2 8 I\ Q [U "3 Q i E Q \,L kg 00 n v K "3 I 1% o Q m n I I l l I smoaoi ifIdNl/JHO/Oi inc/m0 May 7, 1968 J. BERNATT ETAL 3,382,330

OPERATING MECHANISM FOR HIGH VOLTAGE SWITCH Filed July 25,- 1967 4 Sheets-Sheet 4 FIG. 8

INPUT TRAVEL, ROTATION DEGREES I f l I l /0 I0 3O 7O .90 I00 //0 OUTPUT TRAVEL, ROTATION DEGREES (5) United States Patent 3,382,330 OPERATING MECHANISM FOR HIGH VOLTAGE SWITCH Joseph Bernatt, Arlington Heights, and Otto Meister,

Evanston, Ill., assignors to S & C Electric Company, Chicago, 11]., a corporation of Delaware Filed July 25, 1967, Ser. No. 655,791

9 Claims. (Cl. 200-48) ABSTRACT OF THE DISCLOSURE For operating one or more load interrupter switches between open and closed positions a rotatable drum is employed for each switch having a spiral or helical track engaged by a follower to rotate the individual switch.

Among the objects of this invention are: To provide a simple, efficient and economical mechanism for rotating a switch blade between open and closed positions and simultaneously operating a load current interrupter; to arrange for the application of relatively high operating force at the ends of the operating strokes of the switch blade; to provide an overcenter toggle locking effect at each end of the operating stroke; and to connect a driving drum to a driven member connected to the switch blade and to the current interrupter by an arm rotatable with the driven member and engaging at its distal end with a helical track on the drum.

The switch operating mechanism of this invention employs a drum that is rotatable through a complete revolution by suitable driving means. The switch includes a rotatable insulator for swinging a switch blade between open and closed positions and operating a load current interrupter on rotation of the insulator. The arrangement of the disclosed embodiment of this invention is such that the insulator rotates through slightly more than one fourth of acomplete revolution for swinging the switch blade between open and closed positions and for operating the load current interrupter. The axis of rotation of the drum is normal to and spaced from the axis of rotation of the insulator. The drum is concave and has a helical track in the form of a groove for receiving the distal end of an arm that is secured to and rotates with the insulator. The groove has such a configuration that maximum torque is applied to the insulator at the ends of the opening and closing strokes of the switch blade. In addition the ends of the groove are offset slightly to provide an overcenter toggle action to lock the switch blade in its open or closed position. A housing encloses the drum and arm and the portions of the associated driving and driven members to protect the enclosed parts from the weather, contamination, etc. For polyphase operation the required number of mechanisms is employed and they are driven from a common driving means.

In the drawings: FIG. 1 is a perspective view of a load interrupter switch, a portion of another like unit and operating mechanism common to the switches for ope-rating them between the open and closed positions. FIG. 2 is a vertical sectional view, at an enlarged scale, taken generally along the line 22 of FIG. 1. FIG. 3 is a horizontal sectional view taken generally along the line 33 of FIG. 2. FIG. 4 is a view, at an enlarged scale, of the antifriction bearing at the distal end of the operating arm which is connected to the rotatable insulator. FIG. 5 is a vertical sectional view taken generally along the line 55 of FIG. 2. FIG. 6 (sheet 1) is an enlarged view of one end of the helical groove. FIG. 7 shows a curve that defines the relationship between the ratio of the output torque to input torque for the output travel of the illustrated operating mechanism. FIG. 8 shows a curve 3,382,330 Patented May 7, 1968 that indicate-s the relation between the angular input travel and the angular output travel of this operating mechanism.

In FIG. 1 the reference character 10 designates, generally, a load interrupter switch for alternating current 5 power transmission lines operating at voltages at and above 34.5 kv. The load interrupter switch 10 can be constructed as disclosed in US. Patent No. 3,163,736, issued Dec. 29, 1964. However, it will be understood that other switches can be operated using the mechanism of this invention. The load interrupter switch 10 includes an elongated metallic base 11 that carries stationary insulators 12 and 13 near the ends. Line contacts 14 and 15 are mounted at the upper ends of the stationary insulators 12 and 13 to permit connection to line conductors. The stationary insulator 13 also carries a switch blade contact that is indicated, generally, at 17.

Between the stationary insulators 12 and 13 there is positioned a rotatable insulator 18 that is supported at its lower end by a shaft 19. The rotatable insulator 18 and shaft 19 are referred to herein as a driven member. At its upper end the rotatable insulator 18 has a shaft 20 which extends through a switch operating mechanism that is indicated at 21 and the details of construction of which are set forth in the above patent. The shaft 20 operates through a linkage 22 for rotating a switch blade 23 out of and into contact engagement with the switch blade contact 17 and the stationary insulator 13. Connected in series circuit relation with the switch blade 23 and mounted on the stationary insulator 12 and on the switch operating mechanism 21 is a load current interrupter that is indicated, generally, at 24. When the insulator 18 is rotated to open the switch blade 23, opening movement is effected through the linkage 22 to rotate the switch blade 23 in the direction indicated by arrow 25. Before the switch blade 23 disengages the switch blade contact 17, the load current interrupter 24 is operated, as outlined in the patent above referred to, to open the circuit. After the switch blade 23 disengages the switch blade contact 17, it continues in the opening movement and at 26 the switch operating mechanism 21 functions to start to reclose the load current interrupter 24. The closing operation is completed by the time that the switch blade 23 is moved to the switch open position which is indicated at 27. For swinging the switch balde 23 from the switch closed to the switch open position, the insulator 18 and supporting shaft 19 are rotated through slightly more than one fourth of a complete revolution or through 102. This effects a corresponding movement of the switch blade 23. For closing the switch blade 23, the direction of rotation of the insulator 18 and shaft 19 is reversed and to the same extent as for the closing operation.

In FIG. 2 the shaft 19 is shown as extending through a packing gland 28 and into a housing 29 that may be a metallic casting of an appropriate number of parts and suitably mounted on the elongated base 11. The shaft 19 is journaled in upper and lower bearings 30 and 31. An operating arm 32 extends radially from the shaft 19 to which it is clamped by a bolt 33 and keyed by a key 34. At its distal end the operating arm 32 is provided with an antifriction bearing 35, FIG. 4, that extends into a track in the form of a helical groove 36 that is formed at a variable lead angle 0:, FIG. 5, in the surface of a concave drum 37 which is also referred to herein as a driving member. The center of curvature of the surface of the concave drum 37 is indicated at 38 in FIG. 3 which is also the axis of rotation of the shaft 19. The axis of rotation of the concave drum 37 is indicated at 39 in FIG. 2 and it will be noted that this axis extends normal to the axis of rotation of the shaft 19 and is spaced therefrom.

The helical groove 36 extends entirely around the concave surface of the drum 37 at the variable lead angle at indicated in FIG. 5 for the midway position. As shown in FIG. 6 the groove 36 has a socket 40 at each end which is circular and the center of which is indicated at 41 that is offset a distance 1 from the center 42 of the groove 36. The socket 40 is employed for receiving the antifriction bearing 35 at each end of the helical groove 36 to provide an overcenter toggle locking effect for holding the switch blade 23 in either the open or the closed position, as the case may be.

In FIG. 1 a complete load interrupter switch is shown and in addition there is shown a portion of another load interrupter switch. For three phase operation three load interrupter switches 10 are employed and these are suitably mounted in parallel spaced relation with the distances apart being determined by the voltage of the system in which the switches are connected. For conjoint operation interphase shafts 45 are employed for interconnecting the concave drums 37 of the respective switch operating mechanisms. Any suitable means can be employed for conjointly rotating the several concave drums 37 through a complete revolution in one direction or the other for effecting corresponding operation of the respective load interrupter switch 10. For example a drive shaft 46 can be connected, as shown in FIG. 1, to one of the interconnected drums 37. Through a bevel gear assembly 47 the shaft 46 is arranged to be driven by a vertical drive shaft 48 that is rotated by a suitable drive mechanism indicated at 43 which is capable of exerting the necessary operating torque at the required speed for operating the several load interrupter switches 10 to and from the switch closed positions.

FIG. 7 shows graphically the relationship between the ratio of the output torque of the shaft 19 to the input torque applied to the concave drum 37 by the drive shaft 46 and the output travel of the shaft 19 and rotatable insulator 18. For the preferred operation the helical groove 36 extends completely around the concave drum 37 which is arranged to be operated with input travel of a complete revolution or 360 to effect an output travel of 102 for the shaft 19 and insulator 18. The particular curve 51 is drawn for a mechanism in which the ratio of the distance a between the axis of rotation 38 of the shaft 19 and the axis of rotation 39 of the concave drum 37 and the radius R of the concave surface 52 is 1.4. In describing the functioning of the switch operating mechanism it will be assumed that the switch blade 23 is in the open position at 27, FIG. 1. In this position the antifriction bearing 35 is located in the socket 40 at the corresponding end of the helical groove 46 in the concave drum 37. This is an overcenter toggle locked position which is indicated at 53 on curve 51 in FIG. 7. It is necessary to apply sufiicient torque to the concave drum 37 through an angle of 10 for rotating the distal end of the operating arm 32 out of the respective socket 40. This requires a relatively high ratio of output to input torque which is indicated by the position of the point 53 along the ordinate of the curve 51. There is only a slight rotation of the operating arm 32 and shaft 19 in this period during which torsional twist energy is released. At 55 along curve 51 the operating arm 32 begins to rotate from its zero position as indicated by the abscissa in which position the concave drum 37 or driving member has rotated through 10 from the over toggle locked position. This over toggle locked relation is obtained by reducing the lead angle or of the groove 36 to 5.

The curve 51, between point 55 and point 56, represents the output stroke in degrees 9 of the operating arm 32 or the shaft 19 and insulator 18 constituting the driven member. At point 56 the driven member, the insulator 18 and shaft 19 has rotated through an angle of 102 from the initial zero position at which time the drive member or concave drum 37 has rotated through an angle 5 of 350 from point 53. Between points 55 and 56 along curve 51 the lead angle a of the groove 36 varies from instant to instant. For each point of angular rotation of the output travel represented by curve 51 the driven member, comprising insulator 18 and shaft 19, is rolling into the over toggle relationship in which the driving member or concave drum 37 will rotate through an additional 10 to point 57 during which the driven member experiences only a slight rotational movement except for the take-out of torsional twist. At point 57 along the curve 51 the driving member or concave drum 37 has completed one revolution and the driven member is in the overcenter toggle locked position. One closing cycle of the load interrupter switch 10 has been completed with the switch blade 23 having been swung from the position 27 to the fully closed position in contact engagement with the switch blade contact 17. It will be understood that the socket 40 is provided at each end of the helical groove 36 and that at each end of the travel the operating arm 32 moves into an overcenter toggle locked position. This makes certain on the closing cycle of the switch blade 23 that it contacts properly with the switch blade contact 17 and that the limiting stops are reached. When the switch blade 23 is moved to the open position by a reversal of the foregoing steps and the antifriction bearing 35 is moved into the socket 40 at the opposite end of the helical groove 36, the arrangement is such as to make certain that the limiting stop in the open direction is reached and that the switch operating mechanism 21 is latched. At each end of the helical groove 36 the overcenter toggle locked relationship serves to prevent movement of the switch blade 23 and parts movable therewith should the connection of the drive shaft 46 become loose or uncoupled.

For opening the switch blade 23, the drive shaft 46 is rotated through a complete revolution in the opposite direction by the drive mechanism 49. The driven member including the operating arm 32 rotates from the overcenter toggle locked position, indicated at 57 along curve 51, to roll out of this relationship and reaches point 56 with only slight angular rotation except for the release of torsional twist energy with the driving member or concave drum 37 rotating through 10 to reach this position. On further rotation of the driving member or concave drum 37 in the same direction, intermediate point 58 along curve 51 is reached which corresponds to the point at which the switch operating mechanism 21 starts to become recocked for a subsequent opening operation of the load current interrupter 24. When the driven member including the operating arm 32 reaches point 55, the output travel in the opening direction of the switch blade 23 has extended through an angle 0 of 102 while the driving member or concave drum 37 has rotated through an angle 1: of 350 from point 57. By a further rotation of the driving member or concave drum 37 through 10, the driven member including the operating arm 32 moves into the overcenter toggle locked position and returned to point 53 along curve 51. Here the overcenter toggle locked arrangement makes certain that the limiting stops are reached and that the switch operating mechanism 21 is latched. This completes the opening cycle for the switch blade 23 and the opening and closing cycle for the load current interrupter 24.

FIG. 8 shows by curve 61 essentially a linear relationship in rotational degrees between the input travel g5 and the output travel 0. The curve 61 between points 62 and 63 corresponds to the rotation of the driving member or concave drum 37 through the initial 10 between points 53 and 55 along curve 51. Similarly the curve 61 between points 64 and 65 corresponds to the angular rotation of the driving member or concave drum 37 from point 56 to point 57 along curve 51 into the overcenter toggle locked position.

The drive mechanism herein disclosed can be modified to provide for other torque requirements by choosing other design parameters than those specifically referred to herein. For example, the input travel can be increased for a given output travel and the ratio a/ R can be varied. These changes in parameters in turn will change the lead angle a of the helical groove 36. This controls the shape of the curve 51, FIG. 7, and also the slope of curve 61, FIG. 8. The helical groove 36 can be modified to change the ratio at points between the two ends. One purpose for such change is to provide the required increase in mechanical advantage that is required to move the switch blade 23 into and out of high pressure contact engagement with the switch blade contact 17.

What is claimed as new is:

1. Mechanism for operating a switch blade between open and closed positions comprising a driven member connected to said switch blade and rotatable from a first position corresponding to said open position to a second position corresponding to said closed position,

a driving member rotatable about an axis normal to and spaced from the axis of rotation of said driven member and including a concave drum having a helical track therealong, and

an arm secured to and extending from said driven member with its distal end engaging said track.

2. The mechanism according to claim 1 wherein at least one end of said helical track has an offset portion for receiving said distal end of said arm in overcenter toggle relation to hold said switch blade in the corresponding position.

3. The mechanism according to claim 1 wherein said arm moves in a plane containing said axis of rotation of said driving member.

4. The mechanism according to claim 1 wherein the center of curvature of the surface of said concave drum lies along said axis of rotation of said driven member, and

said track is in the form of a helical groove in said surface with said distal end of said arm extending thereinto.

5. The mechanism according to claim 4 wherein each end of said helical groove has an oifset portion for receiving said distal end of said arm in overcenter toggle relation to hold said switch blade in either its open or its closed position.

6. The mechanism according to claim 5 wherein the relation between said helical groove and said arm is such that the extent of rotation of said driving member is substantially greater than the extent of rotation of said driven member between said open and closed positions of said switch blade.

7. The mechanism according to claim 5 wherein the relation between said helical groove and said arm between said offset portions is such that the ratio of output torque of said driven member to the input torque of said driving member is substantially linear over the major portion of the range of rotation of said driven member and is increased at the ends of said range.

8. The mechanism according to claim 1 wherein a housing encloses portions of said driven and driving members and said arm.

The mechanism according to claim 1 wherein plurality of said mechanisms are provided each individual to a switch blade, and

a connection is provided between the drums of said mechanisms to operate the switch blades simultaneously.

References Cited UNITED STATES PATENTS 2,678,975 5/1954 Richardson. 2,830,456 4/1958 Stafford 7457X 2,894,398 7/1959 Ayers 74-57 X ROBERT K. SCHAEFFER, Primary Examiner.

H. l-IOHAUSER, Assistant Examiner. 

